In general, it is desirable for images or a sequence of images (hereinafter referred to as a “video sequence”) captured using an image capture device to be processed, either during capture, or when viewed or played back using video equipment. The processing will generally take the form of filtering or correction of the image or video sequence in order to remove undesirable elements such as motion blur, for example, which may be caused by movement of the image capture device during the capture procedure. Such processing is termed “image stabilization”, and is the process which allows an image or video sequence to be captured, stored or rendered with a reduced (or eliminated) amount of apparent motion caused by the secondary, unintentional motion of the image or video sequence capture device with respect to the scene or object being captured, while preserving the dominant, intentional motion of the capture device. The image or video capture device could be a camera (digital or other), or a camcorder (digital or other), or generally, any device capable of capturing an image or sequence of images for storage in the device or elsewhere.
Image stabilization techniques have been used in a wide variety of different applications, including surveillance applications, vehicle-mounted image sensor applications, robotics applications, and consumer electronics applications. Among the primary classes of image stabilization techniques are mechanical image stabilization methods, electromechanical image stabilization methods, optical image stabilization methods, and electronic image stabilization methods. Some existing electronic image stabilization systems attempt to distinguish between global motion and subject motion, but these techniques are not completely accurate and can create false positive detections of global motion, when in fact the motion was subject motion. When a false positive occurs, an attempted correction is typically performed when it should not have been, which produces an incorrect effect in the stabilized video sequence and correspondingly a less desirable video.
For these and other reasons, a need exists for the present invention.